In working with cables of a variety of types and particularly helical stranded transmission cables, connectors and dead end devices are used. A connector or line splice as it is sometimes called is used to couple adjacent cables. A dead end device is used to grip one end of a cable in order to anchor the same. These can be referred to generally as gripping units and are known in the trade as automatics when the line man need only insert the cable end therein and gripping is achieved without making further adjustments such as tightening of screws or bolts.
A variety of automatic gripping units and devices are available. However, for the most part prior to this invention these were not entirely satisfactory from a functional, convenience and economical point of view. From a functional point of view, the device must be easy to install and grip the cable in a positive manner immediately upon insertion and over long periods of time. The grip must be good mechanically and electrically and must insure against failure. From a convenience point of view it is desirable that one size gripping unit be capable of gripping a range of cables of different size diameters and do so without adjustment and without the use of special tools. From an economical point of view the unit should be inexpensive to manufacture, must have a minimum of parts and not require precise matching and selection of parts. Of course, the ability to use one size gripping unit for several size cables reduces the costs resulting from inventory and production tooling.
One type of cable in common use today is stranded cable in which the strands are twisted so that each of the strands is in the form of a helix. Helically wound stranded cable of this type is especially difficult to hold firmly in a gripping unit.